Pup wont let me touch her feet

Question
Hi Cindy! I have three male dogs (all rescues, neutered), ages 2-6, and recently rescued a female red nose pit bull.  She is my first female pup, first terrier, and gosh... it's been rough!  My boys have always been eager to please and easy to train.  This pup is quite different! :) I have been successfull with modifying most of her behaviors, but for some reason, she WILL NOT let me groom her nails, or check her feet for ticks.  She yelps like she is in great distress, pulls violently away, mouths my hand (not hard), and basically has a complete meltdown.  It's incredibly frustrating for me. I've never cut her toenails too short, and she's never had any feet injuries.  What's going on? How can I keep her calm and make her submit to my grooming her?  Thanks for your help!

Answer
Hello Matt,  Aren't you the greatest for rescuing these dogs.  We need more like you.  As you know rescued dogs have histories that we will never know of.  And that is what I think you are dealing with, something has happened in her past that she just can't get over.  It is a trust issue.  I would limit the nail clipping as this can be threatening to many dogs, but with that said, still do it when needed.  In the off time gently rub her feet, small sessions at a time increasing the time as you go.  Like I said it is a trust issue and for her she needs to build that one lack of trust, because of someone else, in you.  Good luck and Thanks for asking, Cindy Lou :)